The present disclosure relates to a developing device and an image forming apparatus including the developing device. More particularly, the disclosure relates to: a developing device including a toner detection sensor that detects a toner concentration or a remaining amount of toner in a developer container, and a scraper that cleans a detection surface of the toner detection sensor; and an image forming apparatus including the developing device.
In an image forming apparatus, an electrostatic latent image formed on an image carrier composed of a photosensitive member and the like is developed by a developing device so as to be visible as a toner image. As an example of such a developing device, there is a developing device that adopts a two-component developing method using a two-component developer. This type of developing device includes a developer container that contains a two-component developer composed of carrier and toner, a developing roller that supplies the developer to the image carrier, and an agitation conveyance member that conveys the developer in the developer container while agitating the developer, and supplies the developer to the developing roller.
In the developing device, the toner is consumed by the developing operation. Therefore, in order to replenish the toner by an amount consumed by the development, it is necessary to measure the toner concentration in the developer by a toner concentration detection sensor (toner detection sensor) provided in the developer container.
In order to accurately measure the toner concentration, it is necessary to suppress accumulation of the developer on a detection surface of the toner concentration detection sensor. Therefore, the agitation conveyance member is provided with a scraper for cleaning the detection surface of the toner concentration detection sensor. When the agitation conveyance member rotates, the scraper slides on the detection surface of the toner concentration detection sensor to clean the detection surface. When a nonwoven fabric is used as the scraper, the detection surface of the toner concentration detection sensor can be effectively cleaned.
It is noted that a developing device using a nonwoven fabric as a scraper for cleaning a detection surface of a toner concentration detection sensor has been known.